Upload
tranquynh
View
217
Download
0
Embed Size (px)
Citation preview
1SINTEF Energy Research
The Directorate of Public Construction and PropertySINTEF Energy Research – Dept. Energy Processes
CO2 Heat Pumps for Heating and Cooling of Non-Residential Buildings
3/4 1/4 4/4
SuppliedElectricity
Heat Source, Cooling Demand or Thermal Energy Storage
Heating Demand or Surplus Heat
2SINTEF Energy Research
Proposal for New Building Codes (2006)Energy Demand in Buildings – Total Energy Budget [kWh/(m2y)]
41
1527 32 38 38
47 51
9
11
2125
37 3728
4435
355
10
30 30 3010
24
50
31
53
0
20
40
60
80
100
120
140
160
180
Single
fam. h
ouse
sApa
rtmen
t bldg
s.Offic
e bldg
s.Sch
ool b
ldgs.
Hospit
alsNurs
ing H
omes
Hotels
Commerc
ial bl
dgs.
Ener
gy B
udge
t [kW
h/(m
2 y]
Space Cooling
Hot Water Heating
Heating of Ventilation Air
Space Heating
3SINTEF Energy Research
Heat Pumps for Heating and Cooling of Non-Residential Bldgs.
The annual heating demand is covered with high energy efficiency
Seasonal Performance Factor (SPF*) > 3-4
A large share of the annual cooling demand is supplied as a by-product of the heat production from the heat pump or covered by free cooling:
Sea waterGround waterEnergy wells in rock – thermal energy storage
pliedsup
delivered
EQSPF* =
Norsk Hydro, Vækerø
Ericsson-bygget, Asker
Alnafossen kontorpark, Brynseng
Nydalen næringspark, Nydalen
Lena Terrasse. Melhus
4SINTEF Energy Research
CO2 (R744) used in refrigeration and AC systems up to approx. 1950
CO2 Used as a Working Fluid
5SINTEF Energy Research
CO2 Used as a Working Fluid
Reintroduced by professor Gustav Lorentzen (1915-1995)
First patent on a transcriticalCO2 system in November 1988
6SINTEF Energy Research
Carbon Dioxide (CO2)Summary of Main Properties and Characteristics
Low critical temp. (31.1°C) – high critical pressure (73.8 bar)Heat rejection at supercritial pressure → transcritical heat pump cycleHigh pressures at evaporation and heat rejection (25 to 150 bar)
Moderate molar weight (44.01) – very high gas densityCompressor volume only 10 to 25% of conventional compressorsSmall dimensions on heat exchangers and tubing
Favourable thermophysical propertiesExcellent heat transfer → low temp. differences in heat exchangersLow pressure ratio → high compressor efficiency
Other propertiesODP=0, GWP=0 → no negative impact on the global environmentNon-flammable, non-toxic, odourless, inert, stabile → safe fluid
COCO22
7SINTEF Energy Research
CO2 Heat Pumps in Non-Residential Bldgs.Heat Rejection Process in a Temperature-Enthalpy Diagram
Falling return temperature in the heat distribution system increases the COP for the CO2 heat pump ⇒ Serial connection of heat loads at falling temp. levels
Radiators
Reheating DHW
Ventilation batteries
Floor heating syst.
Preheating DHW 5-30°C
30-50°C
50-90°C
8SINTEF Energy Research
Example of CO2 Heat Pump SystemCombined Heating and Cooling – Use of Thermal Energy Storage
9SINTEF Energy Research
CO2 Heat Pump Water HeaterManufactured by Denso Corporation Ltd., Japan (2001-2002)
Hot water heating
Ambient air as heat source
4.5 kW heating capacity
85°C hot water temperature
The world’s first commercial CO2 heat pump
• CO2 technology developed at NTNU-SINTEF, Trondheim
• Shecco Technology™ has exclusive licence rights to the CO2 technology patents
10SINTEF Energy Research
Integrated CO2 Heat Pump”EcoCute” – Manufactured by Denso Corporation Ltd., Japan
Space heating & hot water heating
Ambient air as heat source
6.0 kW heating capacity
65/90°C hot water temperature
200.000 units sold in 2003/2004
• CO2 technology developed at NTNU-SINTEF, Trondheim
• Shecco Technology™ has exclusive licence rights to the CO2 technology patents
11SINTEF Energy Research
CO2 Heat Pumps in Non-Residential Bldgs.Environmental Benefits – Technical Benefits/Challenges
CO2 – environmentally benign and safe
May achieve higher SPF than conventional heat pumpsRequires a relatively low return temp. in the heat distribution system
Serial connection of radiators and ventilation batteries is requiredThe operating time of the ventilation system is a critical parameterA large hot water demand is favourable
Possible to increase the energy efficiency by applying special system design and components, e.g. replacing the throttling valve with an ejector
No temperature limits when supplying heatCan supply heat to high temperature hot water systems (<95°C)Can supply heat to high temperature radiators (80-90°C)